Baxi boiler showing a fault code? Use this reference to identify the issue across every Baxi 200, 600, 800 and Platinum boiler made in the last 12 years.
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🔧 Baxi 200 & 400 Combi Boiler Fault Codes Code Meaning H.01-.00 Loss of communication between gas valve and board H.01-.05 Flow/return temperature difference too high H.01-.08 Flow temperature increasing too fast H.01-.14 Max flow temperature exceeded H.01-.18 No water circulation / sensor fault H.01-.21 Flow temperature rising too fast in DHW H.02-.02 Parameters not configured H.02-.03 Incorrect configuration settings H.02-.04 Parameter fault H.02-.06 Low system water pressure (<0.5 bar) H.03-.00 Communication error with NTC/flue sensor H.03-.01 Communication error with PCB E.00-.04 Return temperature sensor open-circuit E.00-.05 Return temperature sensor short-circuit E.01-.04 Loss of flame 5 times in 24 hrs E.01-.11 Incorrect fan speed E.01-.17 No circulation / sensor fault E.01-.20 Max flue gas temperature reached E.02-.07 No/low pressure (<0.5 bar) E.02-.16 CSU timeout or PCB fault E.04-.00 Gas valve not detected E.04-.01 Flow temp sensor short-circuited E.04-.03 Critical flow temperature reached E.04-.10 Failed to ignite (possible gas fault) E.04-.12 False flame signal E.04-.13 Fan rotor blocked E.04-.17 Gas valve or gas/air unit fault E.270 Dry fire protection triggered
🔧 Baxi 600 & 800 Series (Combi/System) Code Meaning E09 Gas valve connection fault E10 External probe fault E12 Differential water flow switch (open) E13 Differential water flow switch (closed) E15 Gas valve command fault E20 Central heating NTC fault E28 Flue NTC/thermistor fault E40 CH return NTC fault E50 Hot water NTC fault E83–E87 Communication error E109 Pre-circulation fault E110 Overheat or jammed pump E118 Low pressure (<0.5 bar) E125 Circulation fault E128 Frequent flame failure E129 Loss of flame during calibration E130 Flue thermostat tripped (lockout) E133 Ignition/gas supply issue E134 Gas valve open without gas E135 Internal gas supply error E154 Flow/return sensor test fault E160 Fan/fan wiring fault E163 DHW NTC wiring/sensor fault E270 Circulation fault (dry fire) E317 Incorrect mains frequency E321 Hot water NTC fault E384 False flame detected E385 Undervoltage E430 Water pressure test fault
🔧 Baxi Platinum Range (Combi/System) Code Meaning E20 Central heating NTC error E28 Flue/air pressure switch or condensate fault E50 Hot water NTC error E110 Thermostat safety trigger E119 Low water pressure E125 Circulation fault E130 Flue overtemperature E133 Gas supply/flame failure E160 Fan fault E193 Pre-circulation error
🔧 Baxi Duo-tec & Megaflo Boilers Code Meaning E10 Outdoor sensor fault E20 Central heating thermistor fault E28 Flue thermistor fault E110 Boiler overheated E119 Low water pressure E125 Water circulation fault E131 Flue overheat lockout E133 Ignition/gas supply fault E160/E161 Fan fault E164 Pressure sensor fault E167 PCB fault E168 PCB lockout E193 Circulation error
🔧 Baxi EcoBlue (Combi, Advance, Plus, System, Heat) Code Meaning E10 Outdoor sensor error E20 CH thermistor fault E28 Flue thermistor fault E54 DHW flow fault E78 Water pressure sensor fault E109 Poor circulation E110 Overheat E118 Water pressure too low E125 Circulation fault E128 Flame loss E133 Ignition failure E160 Fan fault E162–E166 Air pressure switch fault E270 Dry fire E384 False flame E385 Low voltage
LED versions show:
3 green flashes – Temporary flame loss 2 red flashes – Overheat 4 red flashes – Fan fault 3 red flashes – Ignition failure 🔧 Baxi Assure & Main Eco Compact Boilers (Combi/System/Heat) Code Meaning E09 Gas valve cable fault E15 Gas valve fault E20 Central heating NTC E28 Flue NTC fault E118 Low system pressure (<0.5 bar) E125 Circulation fault E130 Flue thermostat fault (lockout) E133 Ignition/gas supply issue E135 Internal gas error E154 Flow/return plausibility fault E160 Fan fault E270 Dry fire E321 Hot water NTC fault E384 False flame 1–6 RED/GREEN flashes Indicate temperature, communication, or ignition issues depending on pattern
🔧 Baxi Solo (Heat-only, older models still sold into 2015+) LED Pattern Meaning OFF OFF OFF No power FLASH FLASH ON Fan error FLASH OFF FLASH Low voltage FLASH OFF ON Overheat ON FLASH ON Thermistor error ON OFF ON Ignition lockout ON ON ON Wiring harness error ON FLASH FLASH Circulation/dry fire ON ON FLASH PCB fault
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